Investigating Approaches for Balancing Durability and Stability of Asphalt Concrete Mixtures
[Thesis]
Vieira Souza, Denis Iran
Nazarian, Soheil
The University of Texas at El Paso
2020
64
M.S.
The University of Texas at El Paso
2020
Improving the durability and long-term performance of the asphalt concrete (AC) has become a major concern, especially with the increase in the use of recycled materials, warm mix asphalt additives and modified binders. To balance the mechanical properties durability and stability of AC mixtures, mix design approaches that incorporate performance tests are needed. This thesis presents an experimental evaluation of different mix design approaches to balance the mechanical properties of AC mixtures. The current volumetric-based design method was enhanced with performance-based analysis that specifies parameters from the overlay tester, Hamburg wheel tracking device and indirect tension tests. Four typical Superpave mixes that exhibited poor performance especially in cracking, from different plants were selected for this evaluation. The mixtures were first designed following the current volumetric-based design process and characterized under the proposed performance-based analysis. Two alternative approaches that consider the influence of the asphalt content and aggregate gradation were explored to improve the engineering behavior of the mixtures. From this evaluation, mixtures that could potentially yield optimal volumetric and balanced mechanical properties were developed. The optimization of the aggregate gradation is a promising approach to formulate a mixture with balanced stability and durability as judged by its rutting and cracking potentials.